1. Field of the Invention
The invention relates to a spark gap for use in the power supply of medium voltage and low voltage networks, with two rotationally symmetric electrodes which are arranged inside a housing and with an arc space provided between the two electrodes for the arc that is formed in the case of a spark-over and its follow-on current.
2. Description of the Related Art
Such a spark gap is known from DE-PS 29 34 236. In all the embodiments of this publication the arc space in question is positioned as a spark-over place at the edges or sides of the electrodes. A disadvantage of all these embodiments is that the electrical data of the spark gap are fixed. This applies, in particular, to the extinguishing capacity of the follow-up current. Another disadvantage of spark gaps of the abovementioned type, but also of other spark gaps, is that due to greatly different installation sites and also the possibly different connection conditions existing there, in present day practice there are a great many different types of connection and installation means of spark gaps. In the aforementioned publication DE 29 34 236 C2 nothing is mentioned about the mounting or installation of the spark gap. No particulars are furnshed either about the adaptation of such a spark gap to different electrical conditions.
The DE-PS 732 002 shows an overvoltage arrester for use in high-voltage systems. Inside a long, housing-like, cylindrical tube made of insulating material a pin-shaped electrode is provided rotationally symmetrical to same, followed by a tube made of a material which, when heated, gives off gas and finally, at the end of the outer housing tube, a roughly cup-shaped counter-electrode with a blow-out opening. Because of the relatively large distance between the pin-shaped electrode and the cup-shaped counter-electrode, such an overvoltage arrester is suitable only for use in high-voltage systems, but not for use in medium-voltage or low-voltage systems. Also with this overvoltage arrester no particulars are furnished for the adaptation to different electrical conditions.